This study aims to analyze the effect of the BTS Brand Ambassador on product purchasing decisions at Tokopedia with Electronic Word of Mouth as a moderating variable. For FEB students in the 2019 management study program. The type of research is Explanatory Research, the data collection method uses a questionnaire with a sample of 89 respondents and uses a purposive sampling technique. Data analysis used multiple linear regression with Moderated Regression Analysis (MRA). The results of the study show that Brand Ambassador has a positive and significant effect on Purchasing Decisions while the interaction of Brand Ambassador Variables with Electronic Word of Mouth is not able to moderate the Purchasing Decisions.